Test Overview
Test Methodology

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis

Test Usage

Diagnosing individuals with potential increased risk factors for coronary artery disease. A functional assay for folic acid deficiency. Diagnosing homocystinuria. Plasma is the preferred specimen for cardiovascular risk factor and folate functional test. Patients with reduced renal function should be evaluated by quantitating homocysteine in the urine.

Reference Range *

0 - 9 mcmol/g creatinine

Test Limitations

Homocysteine values and their relationship to coronary artery disease are still investigative.

Test Details
Days Set Up
Monday - Saturday
Analytic Time

2 - 5 days

Soft Order Code
HCYSU
MiChart Code
Homocysteine, Urine
Synonyms
  • HCYSU
  • HOMOCYSTEINE, TOTAL, URINE
Laboratory
Sendout
Reference Laboratory
Mayo HCYSU (80378)
Section
Special Testing
Specimen Requirements
Collection Instructions

Collect random urine specimen as follows: Discard first morning urine void following an overnight fast. Continue fasting and collect the next urine void. Place specimen on ice until it can be frozen. Store and transport frozen.

Special Handling

Fasting specimen.

Normal Volume
4 mL urine
Minimum Volume
2.5 mL urine
Additional Information

Large quantities of homocysteine are excreted in urine of patients with homocystinuria due to: Cystathionine-beta-synthetase deficiency, aberrrant B12 metabolism, or N-5,10-methylene-tetrahydrofolate reductase deficiency (many of the patients with this deficiency respond to folic acid supplementation). Folic acid deficiency is characterized by elevated urine homocysteine concentration. Test sent to Mayo Medical Laboratories.

Billing
CPT Code
83090
Fee Code
32109
NY State Approved
No